Over the past two decades, community broadband networks, platform cooperatives, and data cooperatives have emerged as promising models to counterbalance market distortions and power asymmetries in the governance of digital infrastructures, services and data. Drawing on multidisciplinary academic debates, this paper investigates how these grassroots approaches to the development and governance of digital innovations can be further harnessed to foster a good digital society. Both their accomplishments and shortcomings are thoroughly reviewed and critically analysed to illustrate and appraise their potential application into diverse spheres of the digital society (from the governance of high-speed networks to the protection of nonpersonal data). The paper concludes with a research and policy agenda, designed to address the challenges emerging from the analysis. Academic researchers are urged to further advance both the empirical and theoretical investigation of these initiatives to develop a more coherent and robust understanding of their development and sustainability over time. A systemic change in the approach of policymakers is also advocated for, to devise regulatory interventions and policy measures capable of sustaining the diffusion and scaleup of grassroots digital innovations.